The history and stability of atmospheric oxygen.

There are three processes weakly concentration-dependent that keep changes in concentration of atmospheric pressure from being a random walk-inhibition of net photosynthesis by oxygen, the passage of hydrogen through the oxidizing part of the atmosphere before it escapes from the earth, and burial of reduced carbon in anaerobic water. A stronger regulator seems desirable but remains to be found. The cause of the initial rise in oxygen concentration presents a serious and unresolved quantitative problem.